1/* Tests for POSIX timer implementation using another process's CPU clock. */
2
3#include <unistd.h>
4
5#if _POSIX_THREADS && defined _POSIX_CPUTIME
6
7#include <errno.h>
8#include <stdio.h>
9#include <stdlib.h>
10#include <string.h>
11#include <fcntl.h>
12#include <time.h>
13#include <signal.h>
14#include <sys/wait.h>
15
16#include <support/xunistd.h>
17
18static clockid_t child_clock;
19
20#define TEST_CLOCK child_clock
21#define TEST_CLOCK_MISSING(clock) \
22 (setup_test () ? "other-process CPU clock timer support" : NULL)
23
24/* This function is intended to rack up both user and system time. */
25static void
26chew_cpu (void)
27{
28 while (1)
29 {
30 static volatile char buf[4096];
31 for (int i = 0; i < 100; ++i)
32 for (size_t j = 0; j < sizeof buf; ++j)
33 buf[j] = 0xaa;
34 int nullfd = open (file: "/dev/null", O_WRONLY);
35 for (int i = 0; i < 100; ++i)
36 for (size_t j = 0; j < sizeof buf; ++j)
37 buf[j] = 0xbb;
38 xwrite (nullfd, (char *) buf, sizeof buf);
39 close (fd: nullfd);
40 if (getppid () == 1)
41 _exit (2);
42 }
43}
44
45static pid_t child;
46static void
47cleanup_child (void)
48{
49 if (child <= 0)
50 return;
51 if (kill (pid: child, SIGKILL) < 0 && errno != ESRCH)
52 printf (format: "cannot kill child %d: %m\n", child);
53 else
54 {
55 int status;
56 errno = 0;
57 if (waitpid (pid: child, stat_loc: &status, options: 0) != child)
58 printf (format: "waitpid %d: %m\n", child);
59 }
60}
61#define CLEANUP_HANDLER cleanup_child ()
62
63static int
64setup_test (void)
65{
66 /* Test timers on a process CPU clock by having a child process eating
67 CPU. First make sure we can make such timers at all. */
68
69 int pipefd[2];
70 if (pipe (pipedes: pipefd) < 0)
71 {
72 printf (format: "pipe: %m\n");
73 exit (1);
74 }
75
76 child = fork ();
77
78 if (child == 0)
79 {
80 char c;
81 close (fd: pipefd[1]);
82 if (read (pipefd[0], &c, 1) == 1)
83 chew_cpu ();
84 _exit (1);
85 }
86
87 if (child < 0)
88 {
89 printf (format: "fork: %m\n");
90 exit (1);
91 }
92
93 atexit (func: &cleanup_child);
94
95 close (fd: pipefd[0]);
96
97 int e = clock_getcpuclockid (pid: child, clock_id: &child_clock);
98 if (e == EPERM)
99 {
100 puts (s: "clock_getcpuclockid does not support other processes");
101 return 1;
102 }
103 if (e != 0)
104 {
105 printf (format: "clock_getcpuclockid: %s\n", strerror (errnum: e));
106 exit (1);
107 }
108
109 timer_t t;
110 if (timer_create (TEST_CLOCK, NULL, timerid: &t) != 0)
111 {
112 printf (format: "timer_create: %m\n");
113 return 1;
114 }
115 timer_delete (timerid: t);
116
117 /* Get the child started chewing. */
118 if (write (pipefd[1], "x", 1) != 1)
119 {
120 printf (format: "write to pipe: %m\n");
121 return 1;
122 }
123 close (fd: pipefd[1]);
124
125 return 0;
126}
127
128#else
129# define TEST_CLOCK_MISSING(clock) "process clocks"
130#endif
131
132#include "tst-timer4.c"
133

source code of glibc/rt/tst-cputimer3.c